title: [An automatic subregion delineation method for T2 measurement of articular cartilage in the knee].
abstract: OBJECTIVE
  To propose a new method for automatic segmentation of manually determined knee articular cartilage into 9 subregions for T2 measurement.
  
  
  METHODS
  The middle line and normal line were automatically obtained based on the outline of articular cartilage manually drawn by experienced radiologists. The region of articular cartilage was then equidistantly divided into 3 layers along the direction of the normal line, and each layer was further equidistantly divided into 3 segments along the direction of the middle line. Finally the mean T2 value of each subregion was calculated. Bland-Altman analysis was used to evaluate the agreement between the proposed and manual subregion segmentation methods.
  
  
  RESULTS
  The 95% limits of agreement of manual and automatic methods ranged from -3.04 to 3.20 ms, demonstrating a narrow 95% limits of agreement (less than half of the minimum average). The coefficient of variation between the manual and proposed subregion methods was 4.04%.
  
  
  CONCLUSIONS
  The proposed subregion segmentation method shows a good agreement with the manual segmentation method and minimizes potential subjectivity of the manual method.
authors.affiliation: Institute of Medical Information, School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, zzh0630@fimmu.com
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhong
authors.forename: Taihui
authors.initials: T
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Meiyan
authors.initials: M
authors.lastname: Feng
authors.forename: Zhentai
authors.initials: Z
authors.lastname: Lu
authors.forename: Wufan
authors.initials: W
authors.lastname: Chen
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D055815:Young Adult